The conventional hot fusion laser printing process consists of the three basic steps of character generation, character transfer, and character fusion.
Character fusion, within the hot fusion laser printing process, creates a permanent image on the paper by means of a heat fusing station. The heat fusing station operates by transporting paper past a heat plate and then through a heated roller assembly. The heated roller assembly typically presses a free dyed-black plastic powder, called toner, into the paper and permanently fuses them into place by heat. Toner is ordinarily composed of styrene/acrylate polymer, polyvinyl butyryl resin and carbon black.
In contrast to the conventional hot fusion laser printing process, a cold fusion printing process has been developed. Cold fusion printing processes can, however, achieve significantly higher printing speeds in comparison to conventional hot fusion laser printers.
A significant distinction between a hot fusion printing process and a cold fusion printing process lies within the character fusion step. The cold fusion process creates a vapor bath from a fusing agent. The fusing agent then liquifies the toner which is, in ram, absorbed by the paper.
Current cold fusion processes utilize an azeotropic blend of freon and acetone as a fusing agent. Despite the commercial success of the cold fusion printing process, the employment of an azeotropic blend of freon and acetone as a fusing agent has been unsatisfactory. Specifically, the employment of an azeotropic blend of freon and acetone as a fusing agent has led to inferior bonding characteristics and solvent properties. Furthermore, azeotropic blends of freon and acetone present environmental hazards, high costs, a minimal yield, and are in scarce supply.